Memory card electrical contact structure

ABSTRACT

A small, flat rectangularly shaped electronic circuit card, such as one containing non-volatile memory, has a row of contacts mounted on bottom surfaces of a row of recesses extending along a short edge and an adjacent angled corner. At least one of the recesses opens to the angled corner and the remaining recesses open to the short edge. Two surface contacts are included in at least one of the recesses, while the remaining recesses each contain a single contact.

CROSS-REFERENCE TO A RELATED APPLICATION

[0001] This application claims the benefit of provisional applicationserial No. 60/140,963, filed Jun. 24, 1999, which provisionalapplication is incorporated herein by this reference.

BACKGROUND OF THE INVENTION

[0002] This invention relates to a small card containing digital memory,such as a non-volatile flash EEPROM system, having exposed surfaceelectrical contacts that allow easy connection to and removal from areceptacle of a host electronic system or device, particularly portabledevices, in order to provide removable electrical connection between thesystem or device and the memory within the card through the exposedsurface contacts of the card.

[0003] Small memory cards are increasing in popularity for use in smallhand held devices such as cellular telephones, music players and otherpersonal electronic equipment. Memory cards are being made smaller forsuch applications while the size of their individual external surfaceelectrical contacts are not being reduced in size to any significantdegree. This presents a challenge to the design and packaging of suchmemory cards. In a specific example, an existing commercial Multi-MediaCard (MMC) product has been manufactured and sold for a time. The MMChas seven surface contacts extending across a short edge of therectangular card that also includes a cut-off corner. Evolvingapplications for this type of memory card have made it necessary to addseveral external contacts without increasing the size of the card.

SUMMARY OF THE INVENTION

[0004] This has been accomplished by increasing the number of contactsof the row of contacts used on the MMC product while maintaining theposition of the row along the short edge of the rectangularly shapedcard. This maintains a degree of compatibility between the MMC productand the new card, known as a SD Card product. In order to increase thenumber of contacts, two contacts are positioned in the space previouslyoccupied by one and another contact is positioned at the cut off cornerand set back from the card edge a distance that is greater than othercontacts of the row.

[0005] Additional features, objects and advantages of the presentinvention are included in the following detailed description, whichdescription should be read in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is an isometric view of the improved removable memory card,showing its top, front side and left side;

[0007]FIG. 2 is a top plan view of the memory card of FIG. 1;

[0008]FIG. 3 is an expanded view of a portion 41 of the top plan view ofFIG. 2, most accurately showing the structure of its recesses andcontacts;

[0009]FIG. 4 is a sectional view of the memory card of FIG. 1, taken atsection 4-4 of FIG. 2; and

[0010]FIG. 5 is a bottom plan view of the memory card of FIG. 1.

DETAILED DESCRIPTION OF THE MEMORY CARD

[0011] One or more integrated circuit chips (not shown) forming thememory system are encased in a plastic card 11 of generally rectangularshape in plan view with three corners being slightly rounded and thefourth corner being cut to form an angled surface (edge) 13 between afront side 15 and a left side 17. As shown in the drawings, the anglededge 13 intersects the adjacent sides 15 and 17 with substantially thesame angle, about 45 degrees. Ten electrical contacts connected with thememory circuit chip(s) within the card are positioned in nine recessesin the top surface along the front side (edge) 15 and the angled edge13. Because of the small size of the card, two contacts of smaller sizeare positioned in one of the recesses and a single contact of smallersize is positioned in a recess along the angled edge 13. Of course, adifferent number of contacts may alternately be used.

[0012] More specifically, as best shown in FIG. 3, recesses 19-26 areprovided in a row along the front side (edge) 15 and a recess 27 alongthe angled edge 13. Each of the recesses is elongated in a directionperpendicular to the front side 15, provides a recessed bottom surfacethat is parallel with the top surface of the card and has wallssurrounding three sides that make it more difficult for fingers handlingthe card to touch the contacts within the recess. The contacts arepositioned a small distance from the front side (edge) of the card forthe same purpose. But since each of the recesses opens outward throughthe front side 15 or edge 13 of the card, mating contacts of areceptacle (not shown) easily slide into and out of the recesses overthe contacts within them as the card is respectively inserted into orremoved from the receptacle.

[0013] The recesses 20-26 each contain a respective one of rectangularlyshaped electrical contacts 31-37, respectively. In the same areaoccupied by any one of these contacts, two contacts 38 and 39 arepositioned in the recess 19. In this example, the contact 38 ispositioned behind the contact 39. One contact 40 of this smaller size ispositioned in the recess 27 because that recess is shorter than theothers. A front edge of the contact 40 is displaced a further distanceaway from the front card edge 15 than are the other contacts 31-37 and39. Ten contacts are thus positioned across the small width of the cardinstead of just eight contacts of the same width that would fit alongthe front side 15 alone.

[0014] As shown in FIG. 5, a label may be attached to a bottom of thecard 11 in a slight recess 43 provided in the bottom surface for thatpurpose.

[0015] Although the invention has been described as implemented in aspecific card example, it will be understood that the invention isentitled to protection within the scope of the appended claims.

It is claimed:
 1. In a flat rectangularly shaped memory card having, inplan view, first and second pairs of opposing parallel straight edgesforming four corners wherein one of said corners includes an angled edgesegment that intersects adjacent edges of one of each of the first andsecond pairs of edges at acute angles, said first pair of edges beingshorter than said second pair of edges, an electrical contact structurecomprising: a row of nine rectangularly shaped recesses positioned alongone of the first pair of shorter edges and the adjacent angled edgesegment, the recesses being surrounded on three sides by walls, eight ofthe recesses opening on a fourth side to the shorter card edge and theother of the recesses opening on a fourth side to the angled edgesegment, said recesses individually containing a single electricalcontact mounted on a bottom surface except that the recess along theshorter card edge that is furthest removed from the angled edge segmentincludes two electrical contacts mounted on a bottom surface thereof,and wherein the contact in the recess that opens to the angled edgesegment is set back further from the shorter edge than the contacts inthe other recesses in the row.
 2. The memory card electrical contactstructure of claim 1, wherein the two electrical contacts within therecess furthest removed from the angled edge segment are positioned onebehind the other at different distances from the shorter edge.
 3. Thememory card electrical contact structure of claim 1, wherein thecontacts are positioned within their respective recesses with theirfront edges spaced a distance away from their respective shorter edgeand angled edge segment.
 4. A flat rectangularly shaped memory card,comprising: two pairs of opposing parallel straight edges forming fourcorners wherein one of said corners includes an angled edge segment thatintersects adjacent ones of the straight edges at acute angles, aplurality of rectangularly shaped recesses formed in a row extendingalong one of said adjacent straight edges and said angled edge segment,the recesses being surrounded on three sides by walls, at least one ofthe recesses being opened on a fourth side to said angled edge segmentand the remaining ones of the rows of recesses being opened on a fourthside to said one of the adjacent straight edges, and said recessesindividually containing a single electrical contact mounted on theirbottom surfaces except that one of the recesses includes two electricalcontacts mounted on its bottom surface.